In many applications, it is often desirable or necessary to connect several printed circuit boards, or PCBs, together. Such connections are often accomplished using a “through hole” connection, or connector pin via. A pin on the first board is inserted into this via on the second board, which allows signals to travel between the two boards. Two types of these connector pins are commonly used. The first, a press fit connector, is inserted into the via and physically or electrically makes contact with the “barrel” of the via; e.g., a friction fit. The second type is a soldering connection, where the pin is inserted into the via and solder is used to both fill the remaining space and to provide a connection between the pin and the barrel of the via.
Because of the physical structure of such a through hole connection, a connector pin via will often develop a parasitic capacitance. This, in turn, creates a constraint on transmissions that passes through the via. The characteristic impedance of the via is lower than that of signal traces, which creates an impedance discontinuity of the transmission line, with resulting degradation of available bandwidth due to a low pass filter effect of the via capacitance. The result is a reduction in the data rates that can pass through the connection.